Because of the widely varying needs of areas having lighting requirements, it has been found necessary to incorporate adjustability into “standard” lighting systems.
Henderson Jr., et al U.S. Pat. No. 4,173,037 discloses a luminaire lamp support device in which the lamp socket is adjustably mounted on a bracket for adjustment of the socket along a substantially vertical axis. This enables adjustment of the lamp to different positions to obtain various light distribution patterns. The lamp has an outer reflector and an asymmetric inner reflector which is mounted for rotational adjustment about the vertical axis of the luminaire for producing asymmetric distribution of reflected light.
Sholtz U.S. Pat. No. 5,178,452 discloses a lamp designed for surgical operations with an outer reflector which illuminates the area of operation and an auxiliary reflector having an outer diameter which corresponds approximately to the inner diameter of the outer reflector and which is arranged inside the outer reflector to deflect a part of the light beam at a steeper or narrow angle into a surgical wound.
Wijbenga, et al U.S. Pat. No. 5,251,116 discloses a luminaire for creating a primary beam and a secondary beam. Baldwin, et al U.S. Pat. No. 4,943,901 discloses a luminaire with auxiliary reflecting means for reflecting light passing through the top opening and for reflecting such light to illuminate stacked material along the edges of the aisle. Compton U.S. Pat. No. 4,231,080 discloses a luminaire having at least three stack reflector members. Cochran U.S. Pat. No. 1,286,535 discloses a lighting fixture having a outer reflector and a stationary auxiliary reflector.
U.S. Pat. No. 5,582,479 to Thomas et al. discloses a dual reflector high bay lighting system which is designed for operation with a gaseous discharge or high intensity discharge (HID) lamp and employs an outer reflector, that is attached to an upper casing by an adjustable bracket, and an inner reflector that is coaxial with the lamp and is axially adjustable with respect to the lamp base. It is particularly useful in being able to effectively light aisles between storage racks or other arrangements of stacked merchandise which may border such aisles, as illustrated in FIG. 5B.
U.S. Pat. No. 5,791,768 to Splane also discloses a luminaire which utilizes a high intensity or gaseous discharge lamp. It employs coaxially mounted outer and inner reflectors where the inner reflector is adjustable coaxially along the longitudinal axis of the lamp, so as to direct a substantial amount of light onto a first area, while a smaller amount of light is reflected from the outer reflector onto a wider area bordering the first area.
Whereas certain of the lighting devices illustrated and described in the foregoing patents are particularly advantageous for the specific lighting applications, none of them are felt to have addressed the problems of efficiently and economically lighting regions where there is a limited ceiling height as in the parking garages, industrial corridors, washrooms, low overhead storage areas, transit rail or bus stational platforms, maintenance areas or the like. Accordingly, the search has continued for such lighting systems.